1. Field of the Invention
The present invention relates to a method for molding a laminated assembly and apparatus in which a surface skin member is integrally attached to the surface of a resin core member and having a folded part at a peripheral rim of the surface skin member, and more particularly, to a method for molding a laminated assembly and apparatus in which no load is applied to the folded part of the surface skin member when pushing up the laminated assembly, thereby reliably preventing the surface skin member from being peeled off, and consequently having a good appearance.
2. Description of the Related Art
FIG. 10 shows the structure of an automobile door trim in the interior of a door panel. In the automobile door trim 1, a surface skin member 3 is integrally attached to the surface of a resin core member 2 formed to a desired curved shape, and an end of the peripheral rim 3a of the surface skin member 3 is folded over the back of the resin core member 2 at the entire length or part of the peripheral rim of the product for finishing.
As a manufacturing method for the automobile door trim 1, a cold-press molding, a mold-press molding, or other molding methods can be used. The cold-press molding method will be described as an example. First, as shown in FIG. 11, when cold-press molding upper and lower molds (an upper mold 4 and a lower mold 5) are opened, a surface skin conveying unit 6 on which the surface skin member 3 is placed is brought into the cold-press molding upper and lower molds 4 and 5, and the surface skin member 3 is elevated with the motion of a cylinder (not shown) built in the surface skin conveying unit 6, and is retained with a support pin 4a of the upper mold 4.
A thermoplastic resin plate P that is a material of the resin core member 2 being softened by heat, is placed on the die surface of the lower mold 5 prior to supplying the surface skin member 3. As shown in FIG. 12, by closing the upper and lower molds 4 and 5 each other, the resin core member 2 having a desired shape is molded from the thermoplastic resin plate P, and at the same time, the surface skin member 3 is integrally attached to the surface of the resin core member 2.
In this instance, an excessive tensile force is applied to the folded part 3a of the surface skin member 3 held by the support pin 4a as the upper mold 4 moves downward.
Accordingly, recently, a surface skin holding means 7 shown in FIG. 13 is proposed in order to prevent the excessive tensile force from being applied to the surface skin member 3, particularly, to the folded part 3a when the cold-press molding is executed with the cold-press molding upper and lower molds 4 and 5.
In this mechanism, a support frame 7a is supported by a support post 7b. The support post 7b penetrates in a through hole 5a of the lower mold 5, and can be vertically moved. The support frame 7a is constantly urged upward with an urging spring 7c folded over an outer periphery of the support post 7b. When the support frame 7a is pressed downwardly, the support frame 7a moves downward if a pressing force larger than a spring force of the urging spring 7c is applied.
In addition, when the surface skin member 3 is placed, the support frame 7a is elevated to a position forming the same plane as the die surface of the lower mold 5, and when the support frame 7a is at the elevated position, the surface skin member 3 is placed.
As shown in FIG. 14, when the upper mold 4 moves downward to the bottom dead center, and the resin core member 2 and the surface skin member 3 are integrated by closing the upper and lower molds 4 and 5 each other, the folded part 3a of the surface skin member 3 is held by the support frame 7a and the support pin 4a, and is subjected to an appropriate tensile force with the spring force of the urging spring 7c. 
However, when the surface skin holding means 7 comprising the support frame 7a, the support post 7b, and the urging spring 7c is used, as shown in FIG. 15 for example, if the upper mold 4 moves upward after completion of press-molding, the urging spring 7c is released from an external force, so that the support frame 7a is elevated to the uppermost position with the spring force of the urging spring 7c. In this instance, since a laminated assembly a is positioned on the die surface of the lower mold 5, an excessive load is applied to a peripheral rim 2a of the resin core member 2 from the folded part 3a of the surface skin member 3, and as a result, a problem occurs in that the folded part 3a of the surface skin member 3 is peeled off at the position indicated as X.
Also, after the upper mold 4 moves upward, as shown in FIG. 16, the laminated assembly a is pushed up from the lower mold 5 with the pushing-up motion of an ejector pin 5b; however, in this case as well, an excessive load is applied to the peripheral rim 2a of the resin core member 2 from the folded part 3a of the surface skin member 3, thereby the folded part 3a is liable to peel off at the position indicated as X.
Accordingly, in the surface skin holding means 7, although an appropriate tensile force is applied to the surface skin member 3 with the urging spring 7c, an excessive load is applied to the base of the folded part 3a of the surface skin member 3 when the dies are opened after molding and when the surface skin member 3 is pushed up with the ejector pin 5b, with the result that problems occur in that the folded part 3a is peeled off and also a highlighted line cannot be clearly formed, thereby the appearance of the outline of the product is injured.
The present invention has been made in consideration of the above problems, and accordingly, it is an object of the present invention to provide a method for molding a laminated assembly and an apparatus, in which a surface skin member has a folded part at a peripheral rim, wherein when press-molding is executed, the surface skin member is subjected to an appropriate tensile force, so that molding property can be preferably maintained, and also when the dies are opened after molding and when the molded product is pushed up, no excessive load is applied to a base of the folded part of the surface skin member, and consequently, peeling off of the surface skin member can be remarkably prevented.
In order to accomplish the above objects, according to the present invention, there is provided a method for molding a laminated assembly, in which a surface skin member is integrally attached to the surface of a resin core member and a folded part of the surface skin member is folded over the entire length or part of a peripheral rim of the resin core member, wherein the surface skin member is placed above the resin material of the resin core member supplied to a die surface of a lower mold, and when press molding is executed, the folded part of the surface skin member is held with a surface skin holding means provided corresponding thereto, and after completion of the molding, the surface skin holding means moves upward in cooperation with a pushing-up motion of ejector means disposed at the lower mold so as to enable the folded part of the surface skin member to follow the laminated assembly.
As the molding method, there are a cold-press molding method and a mold-press molding method.
In the cold-press molding method, a polypropylene resin plate in which wood meal is mixed is extruded to form a sheet with a T-die extruder, and after the sheet plate is subjected to a hot softening process with a heater and is placed on a cold-press-molding lower mold, it is integrally molded together with the surface kin member supplied into the die by cold-press molding.
In addition, in the mold-press molding method, after the surface skin member is placed in the die, a molten resin is distributed on the die surface of a mold-press-molding lower mold through a hot runner and a gate, and the mold-press molding upper and lower molds are closed each other, thereby integrally molding the resin core member and the surface skin member.
Next, the apparatus for molding a laminated assembly according to the present invention comprises the upper and lower molds for integrally attaching the surface skin member to the surface of the resin core member, the ejector means provided in the lower mold and for pushing up the molded product, and the surface skin holding means provided for the lower mold and respectively corresponding to support pins provided along the peripheral rim of the upper mold, wherein each of the surface skin holding means includes a planar support frame for supporting the peripheral rim of the surface skin member, a support post for supporting the support frame, penetrating in a through hole of the lower mold, and pushed up by an elevating motion of an ejector plate, and a post retaining mechanism for retaining the support post at an elevated position of the support frame.
As the surface skin holding means for holding the peripheral rim of the surface skin member, there are provided the planar support frame provided for the lower mold and corresponding to the support pin provided at the peripheral rim of the upper mold, and the support post attached to the lower surface of the support frame, penetrating in the through hole of the lower mold in a manner so as to be freely and vertically moved, and pushed up with the elevating motion of the ejector plate. As the support-post retaining means at the elevated position, any system capable of locking at a specified position, such as a ball-plunger system and a latch system, can be used.
Therefore, according to the present invention, after the resin core member and the surface skin member have been integrally press-molded, even if the upper mold moves upward, the surface skin holding means does not move upward, so that no load is applied to the folded part of the surface skin member.
In addition, when the laminated assembly is pushed up with the ejector means of the lower mold, the surface skin holding means moves upward in cooperation with the ejector means; therefore, no load is applied to the folded part of the surface skin member even when the laminated assembly is pushed up.
Furthermore, when the surface skin holding means is at the elevated position, even if the ejector pin is accommodated in the lower mold with the support-post retaining means such as the ball plunger, the surface skin holding means is retained at the elevated position, and consequently, the surface skin member can be smoothly placed.